The long term goal of the research program is to apply the knowledge of a well established multidisciplinary team to the advancement of ultrasound methods for evaluating cardiovascular function in health and disease using higher-dimensional ultrasound imaging. The specific goal of this application is to develop and validate multidimensional intracardiac ultrasound imaging software, hardware, and procedures for guiding and evaluating two intracardiac therapies: electrophysiologic myocardial ablation and percutaneous transmyocardial revascularization (TMR). The applicants plant to apply and validate their advanced imaging concepts, a novel ultrasound technology to the two intracardiac therapeutic challenges. The novel technology is a Mayo developed ultrasound cardioscope that is a high-resolution (64 element, 7 MHz, 10F catheter based phased array) intracardiac ultrasound tipped catheter which attaches to a commercial ultrasound imaging instrument which acquires images of properties as flow (power Doppler, color Doppler, PW and CW Doppler), contrast distribution (e.g. fundamental/harmonic contrast) and texture, all from within the internal confines of the animal heart and ultimately the human heart. These data will be used to provide higher-dimensional visualization knowledge of the myocardium including contract distribution through time, texture through time, contrast distribution, vessel morphology and pathophysiology. The applicants proposed to validate metrics (area, depth, width, length, volume, etc., computed from the ultrasound images of ablation lesions and TMR channels in vivo swine hearts, against the same metrics measured from the excised hearts. Subsequently, the applicants will validate the associated knowledge visualization software, hardware, and procedures by applying them to guide and evaluate the two selected state-of-the-art intracardiac therapies in a porcine model. The Mayo developed ultrasound cardioscope, and the applicants' advanced multidimensional imaging methods and hardware have substantial advantages over any other current technology, providing a very high probability of successfully advancing minimally invasive intracardiac therapy within the time frame of this application.